INCREASING THE EFFECTIVENESS OF STUDYING GEOLOGICAL SECTIONS BY RESULTS OF AN ANALYSIS OF STRESS STATE AND GEOLOGICAL AND TECHNOLOGICAL INFORMATION
Abstract
The report is devoted to the problem of studying geological sections. The analysis is based on the results of geomechanical modeling on the base of geological and technological research in the process of drilling wells. The importance of geomechanical modeling lies in the fact that geomechanical modeling can significantly enrich and expand the amount of information about rocks passed during the drilling process and it has recently been a necessary scientific method for analyzing the drilling process, predicting the optimal types of bits and operating parameters, possible complications.
A comparative analysis of theoretical studies of the stress state of rocks is carried out according to a simplified scheme of stress state formation and the state adopted in the framework of the three-dimensional theory of stability of hypotheses, as well as stress calculations using the example of one of the wells of the Karabagly field. Using the appropriate equations, calculations and a comparative analysis of the results for the well drilled in this field were performed. A comparative analysis of the calculation results using known theoretical approaches showed that the difference between the main stresses is maximum on the wellbore contour, which allows us to estimate the place where buckling begins and when the acting stresses exceed the rock tensile strength, the deformation will take the form of plastic flow, forming a limiting region that starts from the walls of the well and is limited by the area of elastic strain.
Information on the stress state in the geological environment can be supplemented by seismic data.
When drilling wells in various geological conditions, there may occur complications associated with abnormally high formation pressures, instability of the walls of the wells, lost circulation due to encounters with permeable layers or hydraulic fracturing. At the same time, geological and technological research of wells allows us to get the information necessary for geomechanical modeling. According to the results of geological and technological studies, dependencies are obtained that express changes of petrophysical (porosity, permeability), strength (hardness, abrasiveness) and elastic (Young's modulus, Poisson's ratio) rock characteristics with depth.
